Home > News > Weigh quantity of processed food against total energy cost

PUBLISHED: 11:33 AM on Wednesday, June 18, 2008

Weigh quantity of processed food against total energy cost

Brain Power

Dr. Sonja Koukel

When the energy crisis hit Juneau, there was some question as to whether the practice of home processing foods would be economically sound. The answer to that question varies according to the amount of product processed, storage availability, and the cost of commercial foods.

Another consideration in these times of rising fuel prices is accessibility to foods. In emergency preparedness, it may be wise to have those food jars lining your pantry shelves to decrease your reliance on foods brought in by plane or barge. Just a thought.

The fishing season is upon us in the Southeast. At this time of year, typically, I remove last season's catch from the freezer and process it in jars. This provides an effective storage life of two years: one year in the freezer, and one year in the pantry.

The amount of product being processed (number or pounds of fish) is one factor in estimating the cost to you. The processing time for half pint or pint jars is 100 minutes at 11 pounds of pressure (psi) when using a dial pressure gauge, or 10 psi when using a weighted gauge. The number of jars that can be processed at one time depends on the size of the pressure canner. Sometimes, a second row of jars can be stacked on top of the bottom row. You will want to use a second canning rack for this, or stagger the jars so the second row sits in-between two jars and not directly on top of the bottom jar. The purpose for this is to allow adequate air flow between the jars. Using this technique, a number of jars can be processed at one time. Thereby, using a minimum amount of energy and/or fuel.

It is possible to estimate the cost of home processing food products using the formula provided:

To calculate the cost of operating an appliance, multiply the wattage of the appliance by the approximate number of hours you operate the appliance (the wattage of an appliance is usually listed on the appliance). Next, divide by 1,000; this will give you the number of kWhs the appliance uses. Finally, multiply the kWh use by the cost per kWh as shown on your electric bill.

We'll use an example of processing pint jars at 2 hours. Calculate: A 8" burner on an electric range is rated at 2,400 watts and is operated for approximately 2 hours for one session.

1. Multiply 2,400 watts by 2 hours (2,400 x 2 = 4,800 watt-hours)

2. Divide the watt-hours by 1,000 (4,800 O 1,000 = 4.8 kWh)

3. Multiply the kWh by the price of electricity. For curiosity sake, we'll use the crisis rate of $0.561 per kWh for the price: 4.8 kWh x $0.561 = $2.69. This translates to about $5.50 for one processing session. At $0.14 per kWh, the total is $0.67, approximately $1.40 for one processing session.

Compare this total cost to the cost of commercial products. True, there is the added expense of catching the fish, purchasing the needed supplies (jars, lids, rings, and so forth), and the time spent preserving the food. All these factor into the total cost of home canning foods. Only you can determine whether this is a time- and energy-efficient process.

Freezing fish and other products is an efficient and effective food preservation method. There are some limiting factors that should be considered when using this method:

 Emergency situations may result in loss of electricity for extended periods of time which means that frozen foods are subject to quality loss and spoilage.

 Freezing is the most expensive method of preserving food. Typically, freezers use any where from 300 - 600 watts depending on the type of freezer (such as, side-by-side or self-defrosting). Use the formula provided to calculate cost.

If you do decide to "can the catch" this season, use the updated resources available through the Cooperative Extension Service. These are available from the website (www.uaf.edu/ces) or pick up copies at the Juneau District office. Remember that all dial gauges should be checked for accuracy once a year. Call the office for more information on this free service, 796-6221.

Dr. Sonja Koukel is the Health, Home & Family Development Program educator for the Cooperative Extension Service UAF Juneau District.

Resources to Remember

"Brain Power" is a new weekly segment focussed on energy conservation and assisting Juneau residents in re-taking control during the energy crisis. Submit your conservation tips and ideas to editor@capweek.com.